German Patent Application DE 199 26 492, not heretofore published, describes a device for producing spun yarn by means of an airflow, wherein a fiber guide is arranged in a block of nozzles. An untwisted sliver emerging from a drafting unit is drawn into the block of nozzles toward an arrangement of a spindle and a sliver guide. In the vicinity of an inlet opening of the spindle, the drafted but untwisted sliver is exposed to an airflow acting in a circumferential direction in the area between the sliver guide and the spindle, thereby is acted upon by a rotating movement. Here, the fibers of the sliver are subjected to the effects of the rotating airflow without controls. Subsequently, this fiber structure is drawn through the spindle for creating a yarn, during which free fiber ends are wrapped around a conically tapered head portion of the spindle and are placed around the fiber structure as covering fibers.
Yarn formation can take place with the spindle at rest, as well as when it is rotating. In the course of wrapping the free fiber ends around the conically tapered spindle head when the spindle is not rotating, a friction force is imposed between the fiber ends and the surface of the spindle head, which restrains their intended rotating movement and therefore can have negative effects, in particular at high yarn speeds. The free yarn ends cannot wrap themselves around the conical spindle head to a sufficient degree and subsequently are insufficiently placed around the draw-off yarn. As a result, the yarn speed during spinning must be limited to avoid deleterious effects on the yarn produced. Although a reduction of the disadvantages caused by such friction can be achieved by utilizing a rotating spindle, a reduction in the yarn strength rather than a desired increase in yarn strength can occur at increasing numbers of revolutions of the spindle in ranges above a certain number of revolutions, for example between 20000 rpm to 30000 rpm. With a completely rotating spindle, a rotating effect can be imposed on the yarn as a result of partial and occasional frictional contact of the interior surface of the spindle with the yarn being drawn off through the spindle inlet opening, which can cause an undesired false twisting of the yarn.